Motors



May 11, 1965 E. E. SOBECK ETAL MOTORS Filed May 14, 1963 m 0 u vm m mlra W 2 6 mm 2 m INVENTORS EUGENE E. SOBECK JACK M. ANDRESEN 5! ATT N YUnited States Patent 3,182,564 MOTORS Eugene E. Sobeck and Jack M.Andrcsen, Winona, Minn., assignors to Lake Center Switch Company,Winona, Minm, a corporation of Minnesota Filed May 14, 1963, Ser. No.280,369 3 Claims. (Cl. 91-421) This invention relates to motors and moreparticularly to stored energy type hydraulically damped motors.

A typical motor of this type may include a spring loaded piston assemblywhich, when released from a cocked position, moves against a hydraulicmedium. The hydraulic medium is released gradually by controlledmetering to limit movement of the piston assembly to a relatively slowuniform rate.

In contrast to the slow movement generally required during the motoringcycle, it is desirable that the piston assembly be capable of beingmoved to the cocked position very quickly.

One common motor of this type includes a cylinder having hydraulic fluidconfined between a pair of spaced apart but connected spring loadedpistons. A metering hub or wall with appropriate ducts and valves ispositioned between the pistons and regulates the discharge of the fluidfrom one side to the other thereof depending on the direction ofmovement of the pistons. This metering hub thus regulates fluiddischarge and the speed at which the cocked spring may move the pistonsto the uncocked position.

In making cylinders of this type difiiculty has been encountered ineconomically sealing the metering wall within the cylinder as well asproviding a check valve of high reliability and durability.

It is therefore a primary object of the invention to provide a novelcheck valve system which allows the hydraulic fluid to be relievedquickly during movement of the driven member to the cocked position butprovides a positive leak proof seal when the driven member is beingmotored.

A further object of the invention is to provide a motor having a checkvalve system which is simple, inexpensive and extremely reliable overextended heavy duty cycling.

A still further object of the invention is to provide a combinationcheck valve and metering hub sealing member.

Other objects of the invention will become apparent from the detailedspecification to follow.

In the drawings:

FIG. 1 is a longitudinal sectional view of a motor of the inventionshowing it in the cocked position with the spring compressed.

FIG. 2 is a longitudinal sectional view showing the motor at thecompletion of its stroke or in the uncocked position.

FIG. 3 is an enlarged fragmentary sectional view of the check valve andsealing member of the motor showing the valve in the closed positionduring the cocked and motoring cycle.

FIG. 4 is a view similar to FIG. 3 but showing the check valve in theopen position while the motor is being moved to the cocked position, and

FIG. 5 is a transverse sectional view showing an end view of the checkvalve and sealing member partially cut away.

With specific reference now to FIG. 1, the motor of the inventionindicated at includes a cylinder housing 11 and a piston assembly 12.The piston assembly 12 comprises a first piston 13 and a second piston14 spaced apart and mounted on a piston rod 15. Both pistons 13 and 14fit with minimum sliding clearance in the cylinder 11 and carry O-ringrubber seals 16.

The piston rod 15 is guided in the cylinder by a stationary cylindricalmetering hub or wall 17 having a guiding bore 18 therein. The hub 17 ispositioned between the pistons 13 and 14 and fixedly held by annularstake marks 19 in the cylinder wall 11 which seat in a mating groove ofthe hub.

A spring 29 engages the end of the piston 13 and urges the pistonassembly 12 from the cooked position of FIG. 1 towards the left, and tothe uncocked position shown in FIG. 2. Tabs 21 struck near one end ofthe cylinder retain the spring in the cylinder.

Initially the piston assembly 12 is held in the cocked position by alatch not shown which may engage a groove in rotatable connector 22.Such connector has a bore 23 therein the bottom of which is engaged bythe piston rod 15 when the piston assembly is being moved toward theuncocked position or when being moved toward the cocked position. Flange24 bent on the end of the cylinder retains the connector in the cylinderby engaging a turned rim 25 on the connector.

To control and limit fast movement of the piston assembly when it isbeing motored, hydraulic fluid 27 is confined in the cylinder betweenthe two pistons 13 and 14, the seal being made by the O-rings 16. Sincethe metering hub 17 is between the pistons 13 and 14, the fluid isactually contained in two separate chambers 28 and 29 which vary in sizedepending on the location of the pistons with respect to the meteringhub.

For passage of hydraulic fluid through the metering hub there isprovided a duct 33 communicating between chambers 28 and 29. Fluid mayalso pass along the clearance provided between the hub and the piston asthe bore 18 is intentionally slightly oversize as shown in FIGS. 3-5.

In use it is desirable for the piston assembly 12 to be able to movefrom the uncocked position shown in FIG. 2 to the cocked position ofFIG. 1 as quickly as possible. On the other hand, in moving from thecocked to the uncocked position of FIG. 2, it is desirable that thespring action be damped and the piston assembly move at a slow'controlled rate.

To accomplish this there is provided a novel valve and seal systemindicated generally at 31 in combination with the metering hub 17.Particularly, the valve 31 is made of a resilient pliable material suchas rubber and formed somewhat in the shape of an annular cap or tirehaving a top 32, a sleeve or annular wall 33 and an inwardly directedannular rib 34 along the side opposite said top. The cap top 32 has acircular opening 35 therein through which the piston rod 15 may pass.

Valve 31 is retained in position by the annular rib 34 which snaps intoa mating groove of the metering hub 17. The hub is also turned to areduced diameter to fit the inside of the valve cap as indicated at 36,FIG. 3. The outside diameter of the valve wall 33 when snapped over thehub is larger than the inside diameter of the cylinder 11. Thus when thehub is inserted in the cylinder, wall 33 compresses tightly against theinside of the cylinder thereby forming a seal. This is extremelyimportant since it has been found very difficult to achieve adequatesealing of the hub by metal staking or swagging operations alone.

Toward the piston 13, the valve cap top 32 extends downwardly over theend of the metering hub a sufiicient distance to overlap the duct 30.When hydraulic fluid is forced from the chamber 29 through the duct 30in the direction Y (FIG. 4) by the piston 14 as the piston assembly isbeing moved toward the right and to the cocked position of FIG. 1, thevalve top 32 will swing or bow '2 outwardly as shown at 37 in FIG. 4.This allow fluid to pass quickly from chamber 29 to chamber 28.

Some fluid will also pass along the clearance between the piston rod andthe bore 18 in the metering hub 17 in the direction Y.

Upon full movement to the cocked position of FIG. 1, the piston assembly12 is held by the latching mechanism not shown which may be inengagement with the connector 22. At such position flow of hydraulicfluid back through duct 30 to chamber 29 is prevented by the valve captop 32 which acts as a check valve. As shown in FIG. 3, the fluid 27firmly presses the top 32 against the flat face 33 of the hub and intight sealing engagement over the duct. The fluid in the two chambers isthus in substantial equilibrium.

When the piston assembly is unlatched, the spring 20 forces against thepiston 13. Movement of the piston 13 exerts pressure on fluid 27 inchamber 28. Such pressure exerts additional pressure on the top 32 ofthe valve cap thereby assuring a tight seal over duct 30.

With duct 30 sealed tightly, the only place the fluid can pass to thechamber 29 is through the clearance afforded between piston rod 15 andhub bore 18 as shown by the arrows X. This restriction acts as ametering valve and restrains fast movement or motoring of the spring andpitson rod. Movement of the piston rod is thus at a controlled uniformrate.

Since the valve top 32 has a closed loop circular opening 35 therein itdoes not have loose corners or flaps under which fluid may pass andthereby provides an extraordinarily good seal. Moreover, greaterstrength and durability are achieved since gradual weakening and tearingof the seal along corners or flap areas is eliminated.

While one embodiment of the invention has been shown, it will beappreciated that it may take other forms without departing from thespirit of the following claims.

What we claim is:

1. A motor including a tubular cylinder, at metering hub fixed withinsaid cylinder and having an axial guide bore therein and a duct therein,a piston rod slideable in said bore, pistons fixed on said piston rod onopposite sides of said metering hub and spaced a distance greater thanthe axial width of said metering hub, a valving member carried by saidmetering hub, said valving member having an annular wall surrounding aportion of said metering hub and located between said hub and saidcylinder, said valve also having a top with an opening therein throughwhich said piston rod may pass, said top extending toward the axialcenter of said cylinder and overlapping said duct in said hub.

2. In a motor having a metering hub sealed within a chamber forcontrolling passage of fluid therepast, said metering hub having a ducttherein extending from one side to the other thereof, a valve carried bysaid metering hub, said valve having a sleeve portion extending axiallyalong an outer portion of said metering hub and in contact with saidchamber for sealing said metering hub with respect to said chamber, saidvalve also having a depending top at substantially rig-ht angles to saidsleeve portion with an opening therein, said top being flexible to sealsaid duct in said metering hub when fluid moves in one direction andbeing resiliently moveable to allow fluid to pass through said duct whenfluid is placed under pressure in the opposite direction.

3. A structure as claimed above in claim 2 wherein said sleeve has a ribextending downwardly toward the axial center of said hub and spacedapart from said top to form a locking ring in conjunction with a matingannular groove in said hub.

Reterences Cited by the Examiner UNITED STATES PATENTS 2,663,309 12/53Filliung 137-525 2,746,477 5/56 Frause et al 137525 X 2,869,873 1/59Tornabene 267-1 X 2,954,043 9/60 Canalizo 137-525 2,989,299 6/61 Modrich2671 X FOREIGN PATENTS 87,136 1/ 5 8 Netherlands.

JULIUS E. WEST, Primary Examiner.

1. A MOTOR INCLUDING A TUBULAR CYLINDER, A METERING HUB FIXED WITHINSAID CYLINDER AND HAVING AN AXIAL GUIDE BORE THEREIN AND A DUCT THEREIN,A PISTON ROD SLIDEABLE IN SAID BORE, PISTONS FIXED ON SAID PISTON ROD ONOPPOSITE SIDES OF SAID METERING HUB AND SPACED A DISTANCE GREATER THANTHE AXIAL WIDTH OF SAID METERING HUB, A VALVING MEMBER CARRIED BY SAIDMETERING HUB, SAID VALVING MEMBER HAVING AN ANNULAR WALL SURROUNDING APORTION OF SAID METERING HUB AND LOCATED BETWEEN SAID HUB AND SAIDCYLINDER, SAID VALVE ALSO HAVING A TOP WITH AN OPENING THEREIN THROUGHWHICH SAID PISTON ROD MAY PASS, SAID TOP EXTENDING TOWARD THE AXIALCENTER OF SAID CYLINDER AND OVERLAPPING SAID DUCT IN SAID HUB.